The Gornergrat (English: Gorner Ridge; 3,135 m (10,285 ft)) is a rocky ridge of the Pennine Alps, overlooking the Gorner Glacier south-east of Zermatt in Switzerland. It can be reached from Zermatt by the Gornergrat rack railway (GGB), the highest open-air railway in Europe. Between the Gornergrat railway station (3,090 m (10,140 ft)) and the summit is the Kulm Hotel (3,120 m (10,240 ft)). In the late 1960s two astronomical observatories were installed in the two towers of the Kulmhotel Gornergrat. The project “Stellarium Gornergrat” is hosted in the Gornergrat South Observatory.